1. Field of the Invention
The present invention relates to a method for forming a metal line and a method for manufacturing a display substrate by using the method for forming a metal line. More particularly, the present invention relates to a method for forming a metal line having low resistance and improved resistance to corrosion and a method for manufacturing a display substrate by using the method for forming a metal line.
2. Discussion of the Background
In general, a liquid crystal display (LCD) apparatus includes a display substrate, an opposite substrate and a liquid crystal layer interposed between the display substrate and the opposite substrate. The display substrate includes a plurality of gate lines, a plurality of data lines crossing with the gate lines, a plurality of switching elements each electrically connected to a gate line and a data line, and a plurality of pixel electrodes each electrically connected to a switching element.
Recently, as a commercially available display apparatus is increasing in size and producing a higher resolution, a resistance-capacitance (RC) delay of a metal line formed on the display substrate may increase. In order to reduce the RC delay, the metal line may include aluminum, which has a relatively low resistance.
However, when the metal line includes aluminum, a defective ratio may increase. Particularly, contact resistance between the metal layer including aluminum and a metal layer including a different metal may be relatively high. Furthermore, aluminum ions may be easily diffused to a silicon layer.
In order to form a fine metal line, a dry-etching process may be used. However, an etchant used in the dry-etching process may damage a metal line formed of aluminum.